IMHO what you should try is excluding all sites with excessive third-party cookies, sluggish performance, and too many ads. That will slice the index down by 80% probably but it would be a really nice thing to see. It might push out low quality SEO results for a couple of years.
This is the solution. Google and DuckDuckGo should be doing this too (and make exceptions if they need to so that they don't collapse). We have to incentivize the good behavior and create an environment where people actually compete on the properties we want and not horseshit.
